What is the vertex form of the equation of the parabola with a focus at (-3,-9) and a directrix of #y=-10#?
The vertex of a parabola is always in between the focus and the directrix
From the given, the directrix is lower than the focus. Therefore the parabola opens upward.
p is 1/2 of the distance from the directrix to the focus
vertex #(h, k)=(-3, (-9+(-10))/2)=(-3, -19/2)
see the graph with directrix
have a nice day from the Philippines